Primary Structural Dissociation - experienced by individuals with PTSD and simple dissociative disorders, such as depersonalization/derealization disorder. Primary structural dissociation indicates the presence of a single ANP and generalized EP.

Secondary Structural Dissociation - experienced by individuals with borderline personality disorder, CPTSD, and some people with OSDD. Secondary structural dissociation indicates the presence of a single ANP and multiple, specialized EPs.

Tertiary Structural Dissociation - experienced by people with DID, and some people with OSDD. Tertiary structural dissociation indicates the presence of multiple, specialized ANPs as well as multiple, specialized EPs.

Dissociative Amnesia - the inability to remember what happened for a significant period of time. Also called "losing time" or "blacking out".

Depersonalization - feeling detached from yourself, or seeing yourself as an "outsider". You may feel detached from your emotion or certain parts of your body.

Derealization - feeling detached from your environment. You may feel that your environment (and people you know) are "not real" or something is "off" about them.

Identity Confusion - feeling unsure, confused, or conflicted about your identity. You may feel as if you struggle to define yourself.

Identity Alteration - a change in identity that may be observable by others. You may experience the alteration as a loss of control, or as a "personality switch".

Losing track of time while watching or reading something.

Inability to remember things before four to five years of age.

Worrying that you'll forget something during a presentation.

Forgetting where you put personal items, such as glasses, keys, or jewelry.

"Highway hypnosis" - forgetting or "spacing out" during an often-taken driving route.

Feeling as if you're reliving the past.

Trouble remembering daily activities.

"Blackouts" in memory, unrelated to substance use.

Hours or days passing that you have no memory of.

Forgetting personal information, such as your name or date of birth.

Looking back at your life and feeling as if pieces or sections are missing.

Feeling as if your childhood memories are "hidden away" inside of you.

"Going through the motions" of work, while feeling like your mind is somewhere else.

Feeling breifly disconnected from yourself during the events of a stressful or traumatic experience, or while under the influence of drugs.

Feeling as if you're living in a dream.

Purposely harming/cutting yourself so that you can feel pain.

Feeling as if you can turn off or detach from your emotions.

Feeling unable to control your behavior, emotions, or actions.

Feeling as if parts of your body are disconnected from the rest of you.

Feeling like a stranger to yourself, or not recognizing yourself in a mirror.

Seeing yourself from a distance, as if you're watching a movie or playing a video game.

Breifly feeling as if the world is unreal or unfamiliar during a stressful or traumatic experience, or while under the influence of drugs.

Feeling detached from other people.

Wondering what is real and unreal around you.

Friends, relatives, or surroundings seeming unreal.

Familiar people or places seem strange or unfamiliar.

Feeling that things around you are changing in size or shape.

Feeling as if people or places around you are "fading away" or disappearing.

Being intellectually aware of who your relatives are, but feeling as if they are not really related to you.

Talking to imaginary friends as a young child.

Having difficulty with juggling all the different roles and responsibilities in your life.

Experiencing cognitive dissonance when saying or doing something you don't agree with.

Feeling like you've been possessed.

Having no idea what you stand for or believe in.

Feeling like you are two entirely different people.

Feeling as if who you are changes from day to day.

Experiencing a struggle inside yourself about who you really are.

Feeling like the "real you" is hidden or locked away inside you.

Having a critical commentary in your head about yourself and your actions.

Feeling as if there are different people inside you, pulling you in different directions.

Acting differently around your parents, at work, with friends, or at home.

Having, or feeling as if you have a public persona and a private persona.

Talking to imaginary friends as an adult.

Not recognizing things that you've written.

Experiencing mood changes that you can't control.

Sometimes speaking in an entirely different voice or style.

Feeling like you inner child sometimes takes control of your behavior.

Having an image of someone inside you, who is different from you or your "ideal self".

Feeling as if you're living a secret life that even your closest friends are unaware of.

The feeling that there are different people inside you who control your behavior or actions.

Presence of two or more distinct alters - at least two distinct identities (called alters or parts) that can "switch" (take control of the body separately).

Dissociative amnesia between alters - "blackouts" during switches. This refers to loss of memory during typically mundane everyday events, and may result in one alter finding "evidence" of other alters existence, such as clothes they don't remember buying.

History of trauma - a history of repeated childhood trauma (including repeated invasive medical procedures or any type of neglect) before the age of approximately nine years old.

Symptoms must cause dysfunction - presence of the previous symptoms must cause some sort of distress or difficulty functioning. This symptom can be helped with therapy.

Presence of two or more less-distinct identity states - at least two distinct identities that can "switch" (take control of the body separately). Identity states in OSDD-1A may present using the same name, but have different ages or "jobs".

Severe dissociative amnesia between identity states - "blackouts" during switches. This refers to loss of memory during typically mundane everyday events, and may result in one identity state finding "evidence" of others' existence, such as clothes they don't remember buying.

History of trauma - a history of repeated childhood trauma (including repeated invasive medical procedures or any type of neglect) before the age of approximately nine years old.

Symptoms must cause dysfunction - presence of the previous symptoms must cause some sort of distress or difficulty functioning. This symptom can be helped with therapy.

Presence of two or more distinct alters - at least two distinct identities (called alters or parts) that can "switch" (take control of the body separately).

No blackout amnesia between alters - there is no complete time loss between alters. People with OSDD-1b will likely experience emotional amnesia and/or gray-outs.

History of trauma - a history of repeated childhood trauma (including repeated invasive medical procedures or any type of neglect) before the age of approximately nine years old.

Symptoms must cause dysfunction - presence of the previous symptoms must cause some sort of distress or difficulty functioning. This symptom can be helped with therapy.

pwDID - "person/people with DID". This phrasing is not exclusive to dissociative disorders, and is often used to refer to different groups of people (ex. pwOCD, pwBPD).

OSDDID - a combination of "OSDD" and "DID". Used as an umbrella term by the community to refer to all complex dissociative disorders. May be combined with the above phrasing ("pwOSDDID") to refer to the community as a whole.

System - a commonly used term online for a person with DID, referring to all of their alters/parts collectively. Some people online may have a "system name" that they use to refer to all parts collectively.

Subsystem - a group of alters/parts who are more separated from the rest of the system by dissociative and amnesiac barriers, and have better levels of communication between their specific group.

Alter - the most common term used for identities within a system. Also called "parts" or "headmates".

Fragment - an alter/part that is less "developed". They may exist to hold one specific memory, aspect of memory, or emotion. They may have a single "job", and may become more developed if necessary. Multiple fragments may each hold different aspects of a single memory.

Introject - an alter/part who has traits (appearance, beliefs, etc.) that are influenced by an outside person or figure. There are two main types of introjects; factual introjects (based on real-life figures, often family members), and fictional introjects (based on fictional characters).

Fronting - one or more alter(s) being in control of the body. It can also be referred to as "(being) in front".

Co-fronting - when two or more alters/parts are in control of the body at the same time.

Co-conscious - also called "co-con". When one alter/part is fronting, and one or more other alters/parts are aware of what is going on, but are not in control of the body.

Passive Influence - when one or more alters/parts influence the opinions, feelings, or behaviors of whoever is fronting.

Blurry - community term. When one or more alters/parts are fronting, but are unsure who they are due to a lack of distinct barriers between identities.

Switching - a different alter/part taking control of the body (fronting).

Splitting - a new alter/part being created. This is triggered by an overwhelming experience that current alters don't have the ability to cope with, and is never voluntary. Different systems may visualize splits occurring internally in different ways, or may not visualize them at all.

Integration - the opposite of dissociation. Information and emotions being accepted and processed. Integration is a healthy process that happens to everyone, and people with complex dissociative disorders have a lowered ability to integrate information due to trauma.

Fusion - two or more alters integrating. This involves the barriers between them being permanently lowered, so they are not separated from each other by dissociation and amnesia. Fusion cannot be forced, but it can happen without consciously trying.

Final Fusion - all alters in a system fully integrating. This involves the barriers between them being permanently lowered, so they are not separated from each other by dissociative and amnesiac barriers. Like fusion, final fusion cannot be forced, and is typically done in later stages of therapy. It is still possible for new splits to occur after final fusion, but much less likely than before, due to a heightened ability to integrate information. Not every system chooses to pursue final fusion, but those who do should have their choice respected.

Internal World - also called an "internal landscape", "inner world", or "headspace". An imagined world (or scene) where alters can interact. A system may or may not have an inner world, and some alters may not be able to access if they do have one. Internal worlds can be highly symbolic or representative of trauma.

Layer - an area of the internal world that is separated from the rest, often by amnesiac barriers. It is often difficult or impossible for certain alters to access certain layers.

NPC - community term. NPCs are entities present in some internal worlds who are not alters, cannot front, and exist within the world as sort of "space fillers". The term is taken from the video game term of the same name, meaning non-playable character.

Large amount of alters, the majority of which are fragments - There is no amount of alters that immediately qualifies someone as being polyfragmented (previously "extremely complex"). The formative paper on polyfragmentation posits that any number over 26 (twenty-six) parts makes someone polyfragmented, but current opinions online are variable. Alter count does not generally have has much of an impact on defining polyfragmentation as the other indicators do.

Splits occur often, and are large in number - a person with pf-DID typically splits new alters/parts much more often than a person who is not polyfragmented. Often, multiple splits will occur at once, sometimes in a pattern. The majority of splits that occur are fragments.

Presence of subsystems - groups of alters/parts who have limited-to-no communication outside their group, tend to occur much more often in people with pf-DID.

Complex internal world structure - the internal world of someone with pf-DID (when one is present) is often expansive, complex, and may contain layers (areas of the internal world that certain alters cannot access). Specific subsystems or alters may exist mainly (or entirely) in specific layers.

History of long-term, severe abuse - people who are polyfragmented have typically experienced abuse that is classified as severe, extreme, or "creative". For more information on this (and other aspects of polyfragmentation), please read "The Phenomenology and Treatment of Extremely Complex Multiple Personality Disorder" by Richard P. Kluft.

Host - an alter who handles most (or large aspects) of everyday life. Some systems may not have a host, or may choose not to label one. Some people may define a host as the alter who fronts the most often.

Co-host - similar to a host. Some systems do not have a co-host, or may choose not to label one.

Protector - an alter who protects other alters from abuse or trauma. This is typically done by either taking the abuse themselves, or by fighting back against it.

Persecutor - an alter who harms other parts inside the system, or harms the body because of maladaptive coping mechanisms or internalized beliefs from experiencing abuse. They are often called "misguided protectors".

Caretaker - an alter who takes care of young or otherwise vulnerable alters. They are typically considered a type of protector.

Internal self helper - an alter who has a lot of knowledge about their system. This could be information about alters, trauma, internal workings of the system, etcetera. Often shortened to ISH.

Gatekeeper - an alter who has control of certain aspects of a system. This could be switching/fronting, memories, subsystems, access to areas of the internal world, etcetera. Gatekeepers are often (but not always) ISH, as well.

Trauma holder - an alter who "holds" memories, emotions, and/or sensations associated with trauma or abuse. Some trauma holders may be stuck in a flashback, and feel like they are permanently trapped in the traumatizing situation(s) that they experienced.

Nonhuman alter - an alter who appears as some type of non-human. This can range from humanoid species like elves or robots, to a species of animal such as a dog or cat, to typically non-sentient objects in their internal world, such as a mountain or bridge.

Little - an alter who is perceived as child-age, and typically "stuck" in a time when childhood trauma occurred. They are also called "child alters/parts".